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Abstract:

A rotary engine comprising an engine block that is movable in rotation
about an axle, said engine block including at least one blind cylinder
mounted on a casing. Said blind cylinders are closed by respective
movable pistons defining sealed chambers of variable volume inside the
cylinders. Each piston is connected to a crank mechanism secured to the
stub axle of the engine block. The variable-volume sealed chamber of each
piston contains a fluid suitable for expanding under the effect of a rise
in temperature, the engine further including heater means for raising the
temperature of the fluid present in said chamber.

Claims:

1. A rotary engine comprising an engine block that is movable in rotation
about an axle, said engine block including at least one blind cylinder
mounted on a casing, said blind cylinder being closed by a movable piston
defining a sealed chamber of variable volume inside the cylinder, each
piston being connected to a crank mechanism secured to stub axle of the
engine block, wherein the variable-volume sealed chamber of each piston
contains a fluid suitable for expanding under the effect of a rise in
temperature, the engine further including heater means for raising the
temperature of the fluid present in said chamber.

2. An engine according to claim 1, wherein the heater means comprise a
stationary heat source arranged on the path of each cylinder in such a
manner as to heat the fluid present in each of the cylinders, in
succession.

4. An engine according to claim 1, wherein the heater means comprise a
susceptor formed by of each cylinder of the variable-volume sealed
chamber, an induction unit being arranged in a fixed position on the path
of each cylinder.

5. An engine according to claim 1, wherein each cylinder includes a
plurality of tubes extending from the cylinder head of each cylinder,
said tubes in each plurality of tubes being in communication with the
variable-volume sealed chamber containing the fluid that is suitable for
expanding under the effect of a temperature rise.

6. An engine according to claim 5, wherein the tubes of each plurality of
tubes are spaced apart from one another by a determined distance so as to
encourage a large flow of air around the tubes.

7. An engine according to claim 1, wherein each cylinder further includes
a diaphragm type deformable sealing gasket comprising a body of flexible
material extending between a bottom portion and a top portion, said top
portion of the gasket being held against the bottom end of the piston,
while the bottom portion of the gasket is held between two flanges of
each cylinder.

8. An engine according to claim 1, further including a brake device for
blocking rotation of the engine block as a function of the position of
each cylinder.

9. An engine according to claim 8, wherein each cylinder includes a
pressure sensor for measuring the pressure of the fluid present in the
variable-volume chamber, the pressure measured by said sensor being
transmitted to a circuit for controlling the brake device.

10. An engine according to claim 1, wherein the fluid is selected from at
least one of the following fluids having a high coefficient of thermal
expansion: Freon, air, helium, hydrogen.

11. An engine according to claim 1, further including a stationary
cooling device arranged along a path of each cylinder.

Description:

BACKGROUND OF THE INVENTION

[0001] The present invention relates to the general field of rotary
engines. The rotary engines that are the most widespread are ignition
engines that rotate about their crank mechanisms that do not rotate. In
such engines, the cylinders are arranged radially.

[0002] The main advantage of this type of engine is low weight, mainly as
a result of excellent cooling because of the cylinders passing through
the air, thereby enabling the weight of the cooling fins to be reduced,
while presenting a moving mass that is sufficient to make it unnecessary
for the engine to have a flywheel. Such engines also present a low level
of vibration compared with an engine having stationary cylinders.

[0003] Nevertheless, at present, rotary engines are considered as being
relatively polluting in that they present very high fuel consumption for
rather low efficiency, and in that they make use of internal or external
combustion. Known rotary engines also require a very large quantity of
lubricating oil.

[0004] Nevertheless, there exists a need for rotary engines that generate
very little pollution and that can be used in various types of
environment (dwellings, vehicles, industrial installations, etc.).

OBJECT AND SUMMARY OF THE INVENTION

[0005] An object of the present invention is to propose a novel design for
a rotary engine that can be driven without requiring internal or external
combustion.

[0006] In accordance with the invention, this object is achieved by the
fact that the rotary engine comprises an engine block that is movable in
rotation about an axle, said engine block including at least one blind
cylinder mounted on a casing, said blind cylinder being closed by a
movable piston defining a sealed chamber of variable volume inside the
cylinder, each piston being connected to a crank mechanism secured to the
stub axle of the engine block, in which engine the variable-volume sealed
chamber of each piston contains a fluid suitable for expanding under the
effect of a rise in temperature, the engine further including heater
means for raising the temperature of the fluid present in said chamber.

[0007] Thus, the rotary engine of the invention may be driven by varying
the volume of the fluid present in the sealed chamber of each cylinder.
Consequently, the engine of the invention pollutes very little in that it
does not make use of internal or external combustion means for driving
purposes and therefore does not exhaust any combustion gas.

[0008] The engine of the invention also requires little maintenance and it
runs very quietly.

[0009] In an embodiment of the invention, the heater means comprise a
stationary heat source arranged on the path of each cylinder in such a
manner as to heat the fluid present in each of the cylinders, in
succession. In particular, the heat source may comprise radiant heater
elements.

[0010] In another embodiment of the invention, the heater means comprise a
susceptor formed by the wall of each cylinder of the variable-volume
sealed chamber, an induction unit being arranged in a fixed position on
the path of each cylinder.

[0011] According to an aspect of the invention, each cylinder includes a
plurality of tubes extending from the cylinder head of each cylinder,
said tubes in each plurality of tubes being in communication with the
variable-volume sealed chamber containing the fluid that is suitable for
expanding under the effect of a temperature rise.

[0012] These tubes serve to increase heat exchange between the fluid
present inside the variable-volume chamber, and the outside.

[0013] Preferably, the tubes of each plurality of tubes are spaced apart
from one another by a determined distance so as to encourage a large flow
of air around the tubes.

[0014] In another aspect of the invention, each cylinder further includes
a diaphragm type deformable sealing gasket comprising a body of flexible
material extending between a bottom portion and a top portion, said top
portion of the gasket being held against the bottom end of the piston,
while the bottom portion of the gasket is held between two flanges of
each cylinder.

[0015] The use of such a gasket serves to improve sealing between the
variable-volume chambers and the remaining portions of the cylinder which
may, under such circumstances, be connected to an oil circulation
circuit.

[0016] In a particular embodiment of the invention, the engine further
includes a brake device for blocking rotation of the engine block as a
function of the position of each cylinder, specifically so as to enable
the cylinders to remain for longer in the stationary heat source, thereby
increasing the pressure of the fluid present in the variable-volume
chambers. Under such circumstances, each cylinder may include a pressure
sensor for measuring the pressure of the fluid present in the
variable-volume chamber, the pressure measured by said sensor being
transmitted to a circuit for controlling the brake device.

[0017] According to a characteristic of the invention, the fluid present
in the variable-volume sealed chamber of each cylinder is selected from
at least one of the following fluids having a high coefficient of thermal
expansion: Freon, air, helium, hydrogen.

[0018] In an aspect of the invention, the engine further comprises a
stationary cooling device arranged on the path of each cylinder in order
to increase the cooling of the fluid present in each sealed chamber
between two successive occasions on which the chamber is heated by the
heater means.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other characteristics and advantages of the invention appear from
the following description of particular embodiments of the invention
given as non-limiting examples and with reference to the accompanying
drawings, in which:

[0020]FIG. 1 is an exploded view of an embodiment of a rotary expansion
engine in accordance with the invention;

[0022] FIG. 3 is a section view of a portion of the engine shown in FIG.
2;

[0023]FIG. 4 is a detail view showing a cylinder of the rotary engine of
FIG. 1;

[0024] FIG. 5 is an exploded view of a piston and connecting rod assembly
of the rotary engine of FIG. 1;

[0025]FIG. 6 is a perspective view of the FIG. 2 engine fitted with a
heating enclosure and a cooling enclosure in accordance with the
invention; and

[0026] FIGS. 7A to 7F show the operation of the FIG. 6 rotary expansion
engine.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0027] The engine of the present invention relies on the principle of the
radial rotary engine known under the name "gnome" engine, but unlike
engines of that type it does not make use of internal combustion.

[0028] FIGS. 1 to 3 show a rotary engine 1 in accordance with an
embodiment of the invention. The rotary engine comprises an engine block
10 of the radial engine type and that is movable in rotation.

[0029] The engine block 10 comprises an engine casing 110 having a
cylindrical side wall 111 with five cylinders 12 to 16 mounted at the
periphery thereof, the cylinders being in communication with the inside
volume 112 of the engine casing 110 via openings 12a to 16a. The
cylinders 12 to 16 are cylinders of the so-called "blind" type in that
their ends remote from their ends fastened to the side wall 111 are
closed by respective cylinder heads 121, 131, 141, 151, 161.

[0030] Respective pistons 20 to 24 are slidably mounted in the cylinders
12 to 16 (FIG. 2). Once mounted in the corresponding cylinder, each
piston 20 to 24 co-operates with the cylinder 12 to 16 to define a sealed
chamber of variable volume 122, 132, 142, 152, 162 that extends between
the free end 20a to 24a of each piston 20 to 24 and each cylinder head
121, 131, 141, 151, 161 of each cylinder 12 to 16 (FIGS. 2 and 4).

[0031] As shown in FIG. 4, each cylinder 12 to 16 is made up of two
portions 123/124, 133/134, 143/144, 153/154, 163/164 connected together
by means of flanges 123a/124a, 133a/134a, 143a/144a, 153a/154a,
163a/164a. Each piston 12 to 16 has on its cylinder head 121, 131, 141,
151, 161 a plurality of tubes 125, 135, 145, 155, 165 communicating with
the respective sealed chambers of variable volume 122, 132, 142, 152,
162. The tubes 125, 135, 145, 155, 165 are of upside-down U-shape, each
forming a fluid duct for a fluid that is present both in the tubes and in
the variable-volume chambers. The tubes 125, 135, 145, 155, 165 are made
of a material having high thermal conductivity, such as aluminum. At
least the portion 123, 133, 143, 153, 163 of each of the cylinders 12 to
16 is preferably made of the same material as the tubes 125, 135, 145,
155, 165.

[0032] Each plurality of tubes 125, 135, 145, 155, 165 serves to increase
significantly the heat exchange area with the fluid present in the
variable-volume chambers 122, 132, 142, 152, 162. The tubes of each
plurality of tubes 125, 135, 145, 155, 165 are preferably spaced apart
from one another at a distance that is determined in such a manner as to
encourage a large amount of air to flow around them, as in the
presently-described embodiment that is shown in particular in FIGS. 1 to
3 and 6. Thus, during rotation of the cylinders, as described below, air
can flow freely around each of the tubes and receive or deliver a maximum
amount of heat.

[0033] As shown in particular in FIG. 5, the ends 20b to 24b opposite from
the free ends 20a to 24a of each piston 20 to 24 are connected to
respective connecting rods 30 to 34. Each connecting rod 30 to 34
comprises a body 301, 311, 321, 331, 341 made up of two portions
3011/3012, 3111/3112, 3211/3212, 3311/3312, 3411/3412, the two portions
of each body being connected together via a respective hinge fork 304,
314, 324, 334, 344. Each body 301, 311, 321, 331, 341 extends over a
determined length between a first end 301a, 311a, 321a, 331a, 341a
connected to the piston and a second end 301b, 311b, 321b, 331b, 341b
extended by a respective connecting rod head 302, 312, 322, 332, 342.

[0034] Each piston 20 to 24 is provided with two annular piston rings
201/202, 211/212, 221/222, 231/232, 241/242 housed respectively in two
grooves 207/208, 217/218, 227/228, 237/238, 247/248 provided in the side
wall of each piston, the piston rings possibly being made in particular
of Iglidur® 30 material and presenting a thickness of 3 millimeters
(mm). The piston rings 201/202, 211/212, 221/222, 231/232, 241/242 serve
to provide sealing between each piston 20 to 24 and the corresponding
cylinder 12 to 16. The piston rings may be held against the inside wall
of each cylinder 12 to 16 by means of resilient rings 2011/2021,
2111/2121, 2211/2221, 2311/2321, 2411/2421 placed in the bottoms of the
grooves 207/208, 217/217, 227/228, 237/238, 247/248 formed in the side
wall of each piston, the resilient rings presenting an outside diameter
that is slightly greater than the inside diameter of the piston rings
(FIG. 4).

[0035] Each free end 20a to 24a of the pistons 20 to 24 is covered by a
respective thermal protection dome 203, 213, 223, 233, 243 having three
walls serving to form two chambers 2031/2032, 2131/2132, 2231/2232,
2331/2332, 2431/2432 for providing thermal decoupling to protect the
piston rings 201/202, 211/212, 221/222, 231/232, 241/242 against the high
temperatures that may exist in the sealed variable-volume chambers 122,
132, 142, 152, 162.

[0036] A diaphragm type deformable gasket 205, 215, 225, 235, 245 is also
mounted between each piston 20 to 24 and the corresponding cylinder 12 to
16. More precisely, the top portion 2051, 2151, 2251, 2351, 2451 of each
sealing gasket 205, 215, 225, 235, 245 is held between two jaws 204/206,
214/216, 224/226, 234/236, 244/246 fastened against each end 20b to 24b
of the pistons 20 to 24 when clamping the first end 301a, 311a, 321a,
331a, 341a of each connecting rod 30 to 34 to the end 20b to 24b of each
piston 20 to 24 (FIG. 4), while a bottom lip 2050, 2150, 2250, 2350, 2450
of each sealing gasket 205, 215, 225, 235, 245 is held between the two
flanges 123a/124a, 133a/134a, 134a/144a, 153a/154a, 163a/164a of the
portions 123/124, 133/134, 143/144, 153/154, 163/164 of each cylinder 12
to 16 (FIG. 4). The side wall 2052, 2122, 2252, 2352, 2452 of each
sealing gasket 205, 215, 225, 235, 245 deforms depending on the position
of each piston 20 to 24 (FIG. 4) in order to prevent any fluid present in
the variable-volume chambers 122, 132, 142, 152, 162 leaking to the
connecting rod and crank mechanism portions of the engine during the
movements of the pistons.

[0037] The diaphragm type deformable sealing gasket 205, 215, 225, 235,
245 may in particular be a gasket made of Rulon® material such as the
gasket sold under the reference BFA 80/70-80 50 MRB by the supplier
Freundenberg Simrit GmbH & Co. KG. In a variant embodiment, the volume
defined between the diaphragm type deformable sealing gasket 205, 215,
225, 235, 245 and the inside wall of the corresponding cylinder 12 to 16
may be filled with oil and connected to a circulation pump (not shown)
for lubricating and cooling the pistons 20 to 24.

[0038] Each connecting rod head 302, 312, 322, 332, 342 is connected to a
respective wrist axle 411 to 415 of a crank mechanism 40 (FIGS. 1 to 3).
In the engine of the invention, the crank mechanism does not rotate. It
is the entire engine block that rotates. For this purpose, the crank
mechanism 40 comprises a two-level turntable 41 disposed on either side
of the crank mechanism heads and movable in rotation about a crank axle
42 by means of a bearing 416 arranged between the turntable 41 and the
crank axle 42 (FIG. 3). The crank axle 42 is secured to a stub axle 17
about which the engine block 10 is designed to rotate. The crank axle 42,
and consequently the turntable 41 of the crank mechanism 40 is eccentric
relative to the stub axle 17.

[0039] A rigid connection between the crank axle 42 and the stub axle 17
is provided by a crank lever 43 that may be secured to the stub axle 17
by means of a screw 431, for example. The stub axle 17 is fastened to a
support structure 18 of the engine. Depending on the intended use, the
support structure may correspond to a structure of a vehicle, of a
stationary installation (building, ground, etc.), etc.

[0040] In the embodiment described herein, the piston 20 of the cylinder
12 is connected to the crank mechanism 40 by a so-called "master"
connecting rod 30 that initially drives the other connecting rods 31 to
34 that constitute "secondary" connecting rods.

[0041] As explained below, the engine block 10 is driven in rotation about
the axle 17. For this purpose, the engine block 10 is supported by the
stub axle 17 via a bearing 19 mounted on the bottom 113 of the casing 110
through which the stub axle 17 passes. The bearing 19 may be adapted to
prevent rotation in the counterclockwise or the clockwise direction in
order to ensure that the engine block 10 rotates in the clockwise or the
counterclockwise direction.

[0042] The casing 10 also includes a cover 114 having a shaft 115 mounted
thereon to take off the rotary motion generated by the engine to be
recovered.

[0043] In accordance with the invention, each variable-volume sealed
chamber 122, 132, 142, 152, 162 respectively of the cylinders 12 to 16 is
filled with a fluid that expands when its temperature is raised, i.e. a
fluid having a high coefficient of thermal expansion. Such a fluid may be
selected in particular from the following fluids: Freon, air, hydrogen,
helium.

[0044] Each piston 20 to 24 includes a filler valve and a bleed valve in
the vicinity of its cylinder head (not shown) in order to enable the
initial fluid pressure in each variable-volume chamber to be adjusted and
in order to enable the chambers to be emptied, where appropriate.

[0045] As shown in FIG. 6, the rotary engine 1 also includes a heat source
constituted by heater means for locally raising the temperature of the
fluid present in the variable-volume chambers 122 to 162 and for driving
the engine block 10. In the embodiment described herein, the heater means
are formed by a stationary enclosure 50 that is mounted, by way of
example, on the support structure 18 and that comprises two panels 51 and
52 placed facing each other. On its surface facing the other panel, each
of the panels 51 and 52 has radiating elements (not shown in FIG. 6),
such as resistive or infrared type heater elements, suitable for creating
a high temperature zone 53 inside the enclosure 50. The outer walls of
the enclosure 50, and in particular those of the panels 51 and 52 are
thermally insulated in order to reduce losses of heat from the enclosure.
In order to encourage heat exchange between the high temperature zone and
the variable-volume sealed chambers, the cylinders 12 to 16, and more
particularly the tubes 125, 135, 145, 155, 165 are made of a material
that is a good conductor of heat and that presents low thermal inertia,
such as aluminum. The wall thickness of the tubes is likewise selected so
as to be relatively fine in order to enable good exchange of heat between
the inside and the outside of the tubes.

[0046] In a variant embodiment, the wall of the cylinder, and more
particularly the walls of the tubes, may act as susceptors and may be
heated rapidly under the effect of induced current on being subjected to
a magnetic field. For this purpose, the wall of each cylinder, or at
least the walls of the tubes should be made of a conductive material that
is suitable for heating rapidly under the effect of induced current.
Induction may be provided by a coil arranged around each plurality of
cylinder tubes. Under such circumstances, the heater means are mounted in
full on each cylinder and they are controlled by a control device that
controls the generation of the magnetic field by each coil, e.g. as a
function of the position of each cylinder as it rotates, as mentioned
above. Alternatively, the induction coil may be arranged separately from
the engine block in a fixed position like the above-described enclosure
50. Under such circumstances, one or more plane induction coils are used
that continuously generate a magnetic field through which the cylinders
pass in succession during rotation of the engine block.

[0047] With reference to FIGS. 7A to 7F, there follows a description of
the operation of the above-described engine 1.

[0048] Initially, the cylinder 12 having its piston 20 connected to the
master connecting rod 30 is positioned in the enclosure 50 so as to
receive heat (FIG. 7A). The fluid present in the chamber 122, and more
particularly in the tubes 125, then increases in temperature and begins
to expand. The expansion of the fluid gives rise to an increase in the
pressure inside the chamber 122, thereby pushing back the piston 20. The
movement of the piston is transformed into rotation by the connecting rod
30 connecting the piston 20 to the turntable 41 of the crank mechanism
40. In response to the force exerted by the connecting rod 30, the
turntable 41 then turns about the crank axle 42, thereby driving all the
other connecting rods 31 to 34 that are connected to the turntable 41. In
the engine of the invention, since the crank mechanism 40 is stationary,
the effect of the connecting rod rotating is to drive the entire engine
block 10 in rotation about the axle 17, in the counterclockwise direction
as represented by the arrow in FIG. 7A. Under such circumstances, the
bearing 19 (FIG. 3) is locked in the clockwise direction in order to
constrain the engine block to rotate in the counterclockwise direction.

[0049] Putting the engine block 10 into rotation in this way causes the
following cylinder, here the cylinder 16, to penetrate into the enclosure
50, as shown in FIG. 7B. The temperature of the fluid present in the
chamber 162 of the cylinder 16, and more particularly in the tubes 126,
then increases in turn. The fluid expands in the chamber 162 and pushes
back the piston 24 which, acting via the connecting rod 34, transmits its
mechanical energy to the turntable 41, thereby imparting rotary drive to
the engine block 10.

[0050] The following cylinders, i.e. the cylinders 15, 14, and 13 pass in
succession through the enclosure 50, as shown in FIGS. 7C, 7E, and 7F.
Each time a cylinder passes through the enclosure 50, mechanical energy
is generated serving to drive rotation of the engine block 10 about its
axle 17. The rotary movement of the engine block 10 may be recovered from
the shafts 114 secured to the cover 113.

[0051] As shown in FIGS. 7A to 7D, when a cylinder, e.g. the cylinder 12,
leaves the enclosure 50, the volume of its chamber, here the chamber 122,
increases until the cylinder is in a position diametrically opposite to
the position it was occupying when it was in position in the enclosure 50
(FIG. 7A). In this position, the volume of the chamber 122 is at a
maximum and the piston is at the end of its stroke. Thereafter, when the
cylinder continues to rotate over the other half of a revolution in order
to penetrate once more into the enclosure 50, the volume of the chamber
122 decreases progressively since the connecting rod 30 pushes the piston
20 towards the cylinder head 121 of the cylinder 12. When the cylinder 12
is once more in position in the center of the enclosure 50 (FIG. 7A), the
volume of the chamber 122 is at a minimum. The fluid present in the
chamber 122 presents little or no opposition to the return of the piston
20 into the chamber 122. During the second half of the rotation of the
cylinder 12 as shown in FIGS. 7D to 7F, the fluid present in the chamber
122 has lost the majority of the heat it received while passing through
the enclosure 50 and it no longer expands. On the contrary, the fluid
begins to cool and consequently to contract.

[0052] In order to accelerate cooling of the fluid in the cylinder
chambers after they have passed through the heater enclosure 50, the
engine of the invention may also include a cooling device 60 arranged
opposite from the enclosure 50, as shown in FIG. 6. The cooling device
may correspond to a bath of cooling liquid through which the cylinders of
the engine pass in succession during rotation, or to a refrigerated
enclosure that defines a low-temperature zone. In order to increase the
efficiency of the bath of cooling liquid or of the refrigerated
enclosure, the cooling device may also be fitted with fans so as to
establish a forced flow of air around the tubes of each of the cylinders.

[0053] When the cylinders are fitted with their own heater means, the
cooling device is placed in a position opposite to the position in which
the heater means are activated during rotation of the engine block.

[0054] The rotary expansion engine of the invention pollutes very little
since it does not exhaust any combustion gas. It also presents relatively
low energy consumption, where its consumption corresponds solely to the
energy needed for powering the cylinder heater means, and optionally the
cooling enclosure when it makes use of active cooling means.

[0055] In a variant embodiment, the engine block 10 is connected to a
brake device that acts in alternation to block and to release the rotary
movement of the engine as a whole as a function of the fluid pressure in
each cylinder when each cylinder is exposed to the source of heat. More
precisely, as shown in FIG. 3, the engine of the invention may be
provided with a brake device 70 comprising a disk 71 secured to the
bearing 19, and a brake member 72 secured to a base that is stationary
relative to the engine block such as the engine support structure 18. The
brake member 72 is suitable for stopping the rotation of the disk 71, and
consequently for stopping the rotation of the engine block 10 as a whole
as a function of the angular position of each cylinder. The disk 71 may
be stopped by the brake member 72 in particular by means of a jaw or by
calipers, or indeed by means for applying an electromagnetic force. The
brake member also includes means, e.g. such as an electronic control
circuit, serving to block rotation of the engine block 10 when one of its
cylinders enters the heater enclosure 50 and to release the disk 71, and
consequentially to release rotation of the engine block, after a
predetermined length of time or when the fluid in the cylinder reaches a
threshold pressure value. Under such circumstances, the cylinders are
fitted with pressure sensors (not shown) serving to measure the pressure
in the variable-volume chamber of each cylinder and to transmit the
measured pressure to the electronic circuit for controlling the brake
member. The brake member also includes means (not shown) for determining
or measuring the angular position of each cylinder in order to block each
cylinder in the heater enclosure. As a result, the engine of the
invention may present operation that is discontinuous with stop/start
stages that are defined as a function of the angle present between two
consecutive cylinders so as to make it possible, in particular, to
achieve optimum heating of the fluid present in the variable-volume
chambers by increasing the length of time each cylinder is exposed to the
source of heat.

Patent applications in class Single state motive fluid energized by indirect heat transfer

Patent applications in all subclasses Single state motive fluid energized by indirect heat transfer